1,721,237 research outputs found
Genetic analysis of seed quality, size, and yield from incomplete partial diallele crosses of Ethiopian mustard (Brassica carinata A. Braun)
No full textEstimates of genetic parameters of oil, protein and total glucosinolate contents, and seed size and weight per plant were determined using a linear mixed model analysis from 81 incomplete partial diallele crosses of 14 parental lines of Ethiopian mustard (Brassica carinata A. Braun) tested at two locations in Ethiopia. All the additive, dominance, and cytoplasmic components of variations and their interactions with the locations were important for all the traits. The additive and cytoplasmic main effects seemed to operate in opposite directions. The former accounted for more than 50% of the variation in oil, but only 13% in protein contents. The two traits, likewise, were genetically antithetical in that lines with increasing effects on oil had decreasing effects on protein or vice versa. This was further illustrated by the negative correlations observed between all the genetic components of the two traits. Notwithstanding this, however, lines with positive genetic effects on both traits were identified thus promising the prospect of improving both traits simultaneously. Oil content and seed size exhibited similar genetic characteristics and were positively correlated, implying the possibility of selecting high-oil genotypes based on their seed size
Geographic pattern of genetic diversity among 43 Ethiopian Mustard(Brassica carinata A. Braun) accessions as revealed by RAPD analysis
No full textAs an oilseed crop, the cultivation of Ethiopian mustard (Brassica carinata) is restricted only to Ethiopia. Even though geographic diversity is a potent source of allelic diversity, the extent of genetic diversity among germplasm material of Ethiopian mustard from different countries has not been assessed. Forty-three accessions, comprising 29 accessions from eight different geographic regions of Ethiopia and 14 exotic accessions from Australia, Pakistan, Spain, and Zambia were analysed for their genetic diversity using random amplified polymorphic DNA (RAPD) technique. A set of 50 primers yielded a total of 275 polymorphic bands allowing an unequivocal separation of every Ethiopian mustard accession. The usefulness of the 50 RAPD primers in measuring heterozygousity and distinguishing accessions was variable such that polymorphic information content (PIC) varied from 0.05 to 0.40, band informativeness (BI) from 0.05 to 0.65 and primer resolving power (RP) from 0.15 to 6.83. Jaccard's similarity coefficients ranged from 0.44 to 0.87 indicating the presence of a high level of genetic diversity. On the average, Australian and Ethiopian accessions were the most similar while, Spanish and Zambian accessions were the most distant ones. Cluster analysis grouped the 43 accessions into four groups, which has quite a high fit (r = 0.80) to the original similarity matrix. With no prior molecular information, the RAPD technique detected large genetic diversity among the 43 accessions from five different countries and their grouping by dendrogram and principal coordinate analysis (PCoA) was inclined towards geographic differentiation of RAPD markers. Conversely, RAPD differentiation along geographic origin was not apparent within the Ethiopian accessions
Genetic analysis of heterosis for yield and yield components in rapeseed (Brassica napus L.) by quantitative trait locus mapping
No full textThe main objective in this research was the genetic analysis of heterosis in rapeseed at the QTL level. A linkage map comprising 235 SSR and 144 AFLP markers covering 2045 cM was constructed in a doubled-haploid population from a cross between the cultivar "Express" and the resynthesized line "R53." In field experiments at four locations in Germany 250 doubled-haploid (DH) lines and their corresponding testcrosses with Express were evaluated for grain yield and three yield components. The heterosis ranged from 30% for grain yield to 0.7% for kernel weight. QTL were mapped using three different data sets, allowing the estimation of additive and dominance effects as well as digenic epistatic interactions. In total, 33 QTL were detected, of which 10 showed significant dominance effects. For grain yield, mainly complete dominance or overdominance was observed, whereas the other traits showed mainly partial dominance. A large number of epistatic interactions were detected. It was concluded that epistasis together with all levels of dominance from partial to overdominance is responsible for the expression of heterosis in rapeseed
Glucosinolates and other seed quality traits of resynthesized Brassica napus L. derived from domesticated and wild Brassica taxa
No full textResynthesized Brassica napus L. genotypes can be used to increase the variation in the rapeseed genepool. We evaluated seed quality parameters of resynthesized lines that originated from crosses of oilseed B. rapa L. with domesticated (vegetable) B. oleracea L., and resynthesized lines that were obtained from crosses of B. rapa oilseed cultivars with wild B. oleracea ssp. oleracea and with seven Brassica species from the B. oleracea group (B. bourgeaui Kuntze, B. cretica Lam., B. incana Ten., B. hilarionis Post, B. montana Pourret, B. rupestris Raf., B. villosa Bivona-Bernardi). Twenty-three resynthesized lines and ten cultivars were grown in 1 year and six locations in Germany and the United Kingdom. The mean seed oil, phytosterole, and sinapine contents of the resynthesized lines were lower than in the cultivars, while protein, glucosinolate, and erucic acid contents were higher, respectively. Nearly all resynthesized lines derived from wild Brassica taxa showed a glucosinolate pattern very different from all cultivars and from nearly all resynthesized lines obtained from crosses with domesticated B. oleracea. The newly developed wild Brassica based resynthesized lines represent an immense source of genetic variation that has not been used to full capacity up to now
Effect of full‐sib and S2‐selection on a sweet corn population (Zea mays convar. saccharata)
No full textAbstract Sweet corn breeding goals differ from grain or silage corn. Sweet corn goals focus on marketable yield including several quality traits. This study explores the effect of a single cycle of full‐sib selection and S2 selection on improving the marketable yield of an open‐pollinated sweet corn population. The selected populations were subsequently compared in four environments for several plant‐, yield‐ and quality traits relative to the original population. Analysis of variance was used to detect selection progress and indirect effects of selection. Full‐sib and S2‐selection decreased total yield. Marketable yield was decreased more by S2‐selection than by full‐sib selection. Flowering time was changed by full‐sib selection, but not by S2‐selection. Full‐sib selection improved ear quality by increasing ear length, the diameter of the ear and the number of kernel rows. S2‐selection showed no effect or a negative effect on ear quality. The application of a single cycle of selection using either method seemed inadequate for increasing marketable yield. More cycles might be necessary to make significant improvements.Funder:
Software AG – Stiftung
https://doi.org/10.13039/50110001454
Spontaneous outcrossing in tomato depends on cultivar and environment and varies between individual flowers
No full textKnowledge about the degree of spontaneous outcrossing of diverse genotypes is essential for breeding programmes, maintenance breeding, and seed production. For tomato (Lycopersicon esculentum Mill.), very limited scientific evidence for genotypic differences is available and evidence from Europe is scarce. To close this knowledge gap, six cultivars were investigated in three Central European locations as part of the Organic Outdoor Tomato Project. To determine outcrossing rates, the monogenetic “cut‐leaf” trait, which is dominant over the “potato‐leaf” trait, was used as morphological marker. The observed range of outcrossing was 0.0%–5.2%. Outcrossing was significantly influenced by cultivar and environment. The outcrossing rate of individual flowers varied within cultivars ranging from 0% to 37%. The potential of newly opened flowers to accept foreign pollen varied largely with the cultivar. Genotypic differences could partly be linked to flower morphology traits. The potential for recombination between tomato genotypes is generally very low but can be a source for new variation in on‐farm management
Influence of Oleic Acid Content on Yield in Winter Oilseed Rape
No full textWinter oilseed rape (Brassica napus L.) with a high oleic (>75%) and/or low linolenic acid (similar to 2%) content in the seed oil is of interest for nutritional and technical purposes. We analyzed whether a change in seed fatty acid composition has a direct influence on yield. Parental lines with different fatty acid composition were crossed, the segregating F-2 populations were divided, and F-3 bulks with contrasting fatty acid profiles were tested in two experiments. In Experiment 1, we developed four bulks in each of three crosses, which varied in oleic (58 to 82%) and linolenic (2 to 11%) acid content. F-3 bulks were tested for 2 yr at three locations in Germany. In Experiment 2, two F 3 bulks each were developed in 16 segregating F-2 populations with high (74 to 79%) and low (59 to 64%) oleic acid content. F-3 bulks were tested for 1 yr at five locations. The seed linolenic acid content did not significantly affect yield. In both experiments high oleic acid content was negatively associated with yield (with a reduction of 1.7 deciton [dt] ha(-1) and 2.0 dt ha(-1) of high versus low oleic acid bulks in Experiments 1 and 2). High oleic bulks exhibited a significantly increased oil content (+0.6%). Yield was negatively correlated with leaf and seed oleic acid content (r = -0.52 and r = -0.48, respectively). Seeds with high oleic acid content showed a significantly retarded germination. Breeding high oleic varieties could be complicated by the negative correlation between yield and oleic acid content
Breeding of Brassica rapa for Biogas Production: Heterosis and Combining Ability of Biomass Yield
No full textThe use of plant biomass as substrate for biogas production has recently become of major interest in Europe. Winter Brassica rapa produces high early biomass and could be grown as a pre-crop harvested early in the year followed by a second crop such as maize. The objectives of this study were to estimate heterosis and combining ability of 15 European winter B. rapa cultivars for biomass yield at end of flowering. A half-diallel without reciprocals was conducted among cultivars to produce 105 crosses. These crosses and their parents were evaluated in two years at two locations in Northern Germany. Data collected were days to flowering (DTF), fresh biomass yield (FBY), dry matter content (DMC) and dry biomass yield (DBY). The mean DBY was 5.3 t/ha for the parental cultivars and 5.6 t/ha for their crosses. The crosses surpassed on average their parents by 7.6% for FBY and 5.9% for DBY whereas DMC was 1.4% higher in the parents. Maximum mid parent heterosis was 21.0% for FBY and 30.4% for DBY. Analysis of variance showed that genetic variance was mainly due to specific combining ability (SCA). The correlation between parental performance and general combining ability (GCA) was 0.42 for FBY and 0.53 for DBY. In conclusion, the amount of heterosis in crosses between European winter B. rapa cultivars is not very high on average, but can be up to 30% in the best crosses. Selection of parental combinations with high specific combining ability to produce synthetic cultivars can rapidly improve biomass yield.KWS Saat AG, Einbeck; FNR (Agency for Renewable Resources) German
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